can anyone offer performance tips to improve the running time ?
this function opens a file (a 7000 row by 30 col), and stores each elements in a matrix data . current running time is 4 sec, and i desperately need to minimize the running time as i need to iterate thru
thousands of such files please help, thanks

C Syntax (Toggle Plain Text)

void iocsv(vector<vector<double> >& data, string path)
{
     string s;
     ifstream inFile;
 
     inFile.open(path.c_str());
     if (inFile) {
         while (getline(inFile, s)) {
               vector<double> col;
               tokenizer<escaped_list_separator<char> > tok(s);
                    for (tokenizer<escaped_list_separator<char> >::iterator beg=tok.begin(); beg!=tok.end(); ++beg) {
                        istringstream price;
                        price.str(*beg);
                        double x;
                        price >> x;
                        col.push_back(x);
                    }
               data.push_back(col);
         }
     }   else { cerr << "Warning: cannot open file "  << path << endl;
                cerr << "Program terminating ......" << endl; }
 
     inFile.close();
}

void iocsv(vector<vector<double> >& data, string path) { string s; ifstream inFile; inFile.open(path.c_str()); if (inFile) { while (getline(inFile, s)) { vector<double> col; tokenizer<escaped_list_separator<char> > tok(s); for (tokenizer<escaped_list_separator<char> >::iterator beg=tok.begin(); beg!=tok.end(); ++beg) { istringstream price; price.str(*beg); double x; price >> x; col.push_back(x); } data.push_back(col); } } else { cerr << "Warning: cannot open file " << path << endl; cerr << "Program terminating ......" << endl; } inFile.close(); }